Deceleration detector

ABSTRACT

A regenerative gas turbine engine has a burner apparatus with a combustion zone and a dilution zone therein and valve means for controlling the amount of air flow into the combustion zone under the control of a deceleration detector including a pressure sealed housing with a movable diaphragm therein forming first and second pressurizable chambers one of which senses discharge pressure of a compressor driven by gas turbine means responsive to vehicle deceleration produced by reduced fuel flow to the burner apparatus. Orifice means in the diaphragm controls pressurization of the chambers by the compressor and spring means are operative to maintain contacts closed during steady state and increasing compressor discharge pressure modes of operation so as to condition the valve means for increased air flow to the combustion zone and the orifice means serve to produce an imbalance of pressure across the diaphragm under vehicle deceleration conditions so as to open the contacts and thereby condition the valve means to reduce air flow to the combustion zone.

United States Patent Huellmantel Sept. 2, 1975 DECELERATION DETECTOR[57] ABSTRACT [75] Inventor: Louis W. Huellmantel, Warren, Aregenerative gas turbine engine has a burner appa- Mich. ratus with acombustion zone and a dilution zone Assigneez General MotorsCorporation, therein and valve means for controlling the amount ofDetroit Mich air flow into the combustion zone under the control of adeceleration detector including a pressure sealed [22] Filed: Oct.15,1974 housing with a movable diaphragm therein forming [21] pp No 514426 first and second pressurizable chambers one of which sensesdischarge pressure of a compressor driven by gas turbine meansresponsive to vehicle deceleration [52] U.S. Cl. 60/3923; 60/3927;60/3929 produced by reduced fuel flow to the burner appara- [51] int.Cl. F02c 7/110 tus. Orifice means in the diaphragm controls pressur-[58] Field of Search 60/3923, 39.27, 39.29 ization of the chambers bythe compressor and spring means are operative to maintain contactsclosed dur- [56] References Cited ing steady state and increasingcompressor discharge UNITED STATES PATENTS pressure modes of operationso as to condition the 2 812 637 11/1957 Fox 60/3923 x valve means forincreased air flow to the combfstion 6/1971 Amann U 60/3927 X zone andthe orifice means serve to produce an imbal- 3691762 9/1972 Ryberg60/3923 X ance of pressure across the diaphragm under vehicle 3,795,1043 1974 McLean 60/3927 ler i n conditions so as to p the contacts nPrimary Examiner-Clarence R. Gordon Attorney, Agent, or Firm-J. C. Evansthereby condition the valve means to reduce air flow to the combustionzone.

3 Claims, 3 Drawing Figures DECELERATION DETECTOR This invention relatesto regenerative gas turbine engines and more particularly to improvedmeans for controlling burner apparatus therein in response to vehicledeceleration.

In control of regenerative gas turbine engines. variable geometryburners are employed to reduce exhaust emissions. One approach has beento include a movable valve element to control the flow of primary airinto a combustion zone of the burner. The gas compressor for theregenerative engine decelerates under certain conditions and in thiscase it has been found desirable to position the valve element into aclosed position to minimize air flow into the burner combustion zoneunder vehicle deceleration conditions and to position the valve openduring vehicle acceleration to pro duce more air flow as more fuel isdirected to the burner. Various fuel controllers have been proposed toregulate air/fuel ratio to the burner of a gas turbine engine. Suchcontrollers have utilized various engine operating parameters such assensing the temperature of exhaust gases from the burner apparatusand/or compressor discharge pressure so as to maintain a desired controlof the ratio of air/fuel flow to the burner apparatus.

An object ofthe present invention is to provide a simplified controlapparatus for maintaining a controlled air/fuel ratio to the burnerapparatus of a gas turbine engine by the provision of a deceleratordetector including means for detecting steady state and increasingcompressor discharge pressure as a basis of operation and valve meansresponsive thereto to increase the flow of air from a compressor intothe burner apparatus combustion zone to maintain a predeterminedair/fuel ratio therein and further including means responsive to adecrease in compressor discharge pressure reflecting a decrease in fuelflow to the burner apparatus combustion zone as occurs at vehicledeceleration to control the valve means to reduce the amount of air flowinto the combustion zone so as to maintain the desired air/fuel ratiounder vehicle deceleration conditions.

Still another object of the present invention is to provide an improvedair/fuel ratio controller in a gas turbine engine operative in responseto compressor discharge pressure to vary the amount of air flow into thecombustion zone of burner apparatus so as to maintain a desired air/fuelratio thereto by the provision of a detector having a gas tight bodythat houses a diaphragm to define first and second pressure chambers oneof which is in direct communication with compressor discharge pressureand the other of which is maintained under a balanced pressure by flowacross orifice means and wherein a pair of contacts are operated by thediaphragm and maintained normally closed by spring means during steadystate. balanced pressure conditions to complete an energization circuitto means for controlling a valve that will maintain increased air flowto the combustion zonc during vehicle operations wherein the compressoris operated to produce a steady state discharge pressure or anincreasing discharge pressure and wherein the orifice means responds toa decreasing compressor discharge pressure to produce a pressureimbalance across the diaphragm to condition the contacts open thereby tocause the valve means to reduce the amount of air flow to the combustionzone under vehicle deceleration operation (ill thereby to maintain adesired air/fuel ratio in the combustion zone.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings wherein a preferred embodiment of the present invention isclearly shown.

FIG. I is a diagrammatic view of a regenerative gas type turbine engineincluding the present invention;

FIG. 2 is an enlarged, fragmentary cross sectional view taken along theline 22 of FIG. 1, and

FIG. 3 is an enlarged cross sectional view of a deceleration detectorused in the present invention.

Referring now to the drawings, in FIG. I a regenerative type gas turbineengine as illustrated including a compressor 12 having an inlet 14 andan outlet connected to a discharge conduit 16 connected to one end of afirst heat exchange pass 18 in a regenerator 20. The regenerator pass 18is connected by an air supply conduit 21 to an outer case 22 for acombustion or burner apparatus 24. The burner apparatus 24 includes aninner liner 26 that has a combustion zone 28 therein in communicationwith a plenum 30 defined by the outer case 22 around the liner 24 acrossa plurality of primary air ports 3], 32 therein for supplying primarycombustion air to the combustion zone 28. A fuel supply for theapparatus 24 is defined by a fuel line 34 connected across a fuelcontrol valve 36 to a fuel supply nozzle 38 for directing fuel into thecombustion zone 28 under the control of an accelerator throttle 40coupled to valve 36. The throttle 40 controls the valve 36 to directfuel into the combustion zone 28 to provide an air/fuel ratio in thecombustion zone 28 for maintaining a temperature of combustion to retardthe formation of nitrogen oxides by combination of nitrogen and oxygenpresent in the air supply to the engine. Burner apparatus 24 furtherincludes a plurality of secondary or dilution air ports 42 therein thatsupply air into a dilution zone within the liner 26 downstream of thecombustion zone 28. A burner exhaust 44 directs combustion productsacross a gasifier turbine 46 connected to a shaft 48 that is coupled tothe compressor 12 for driving it during burner operation. Exhaust fromthe gasifier turbine 46 is directed through a power turbine 50 thencethrough an exhaust conduit 52 across a second heat exchanger pass 53 ofthe regenerator 20 thence through an exhaust conduit 54 to atmosphere.

The power turbine 50 has an output shaft 56 that is coupled to a powertrain for a vehicle.

Referring now to FIG. 2, the air flow to the combustion zone 28 is underthe control of an annular valve sleeve 58 that includes a plurality ofports 60 at circumferentially spaced points therearound that are locatedin overlying relationship to the primary air flow ports 32 to controlthe proportion of air flow through the primary air ports 32 and dilutionports 42 from the plenum 30. The sleeve 58 as illustrated in FIG. 2 isin a closed position wherein the primary air ports 32 are blocked by aplurality of intermediate land portions 62 on the sleeve valve 58between each of the ports 60 therein. A radially outwardly directed lug64 on the sleeve 58 is pivotally connected to one end of a link 66 thathas its opposite end pivotally connected to an output shaft 68 of afluid motor 70 including a cylinder 72 having a piston 74 slidablysupported therein for opposite reciprocation between the closed positionshown in solid line in FIG. 2 and an open. position shown in dot- 68 anddivides the cylinder 72 into chambers 76. 78

communicated respectively by fluid lines 80, 82 that are connected to athree-way solenoid valve 84. When the sleeve 58 is in a closed position,the valve 84 is p'o'si-. tioned to communicate a pressurized sourceofair86 through the pressure conduit 82 into the chamber 78 to force thepiston 74 to the left as shown in solid line in FIG. 2. Chamber 76 isthen in communication with an exhaust port 88 of the valve 84.Conversely, when the fluid motor is conditioned to open the sleeve 58the valve 84 will direct pressurized air from the source 86 through theconduit into the chamber 76 and the chamber 78 will be exhausted throughthe port 88 to move the piston 74 to the right as shown in dotted linein FIG. 2. This will rotatesleeve'valve 58 to communicate ports 32, 60.

1n the illustrated arrangement the solenoid valve 84 is under thecontrol of a deceleration detector 90 including a pressure sealedhousing made up of a first cover 92 of cup-shaped configurationincluding a peripheral flange bent over at 94 into pressuresealedrelationship with a radially outwardly directed flange 96 on ahousing member 98. Housing member 98 includes a signal port 100 thereonthat is communicated through a signal line 101 to sense compressordischarge pressure in the conduit 16. The housing has a movable flexiblediaphragm 102 therein with its peripheral edge press fit in sealingrelationship between the flange 96 and the flange 94. The diaphragm 102separates the housinginto first and second pressure chambers 104. 106. Ableed orifice 108 is formed in the diaphragm 102 to equalize thepressure between the chambers The housing member 92 has an electricalcontact 110 supported thereon connected to a terminal 112 that iselectrically connected by a wire 114 to the solenoid 116 of the valve84. The terminal 112 is electrically insulated from the body 92. Asecond contact is secured to the diaphragm 102 by suitable meansrepresentativel'y shown as a rivet l 16 so as to be moved with respectto the contact 110 between open and closed positions therewith. Thecontact 115 is connected by meansof a wire 118 to -a second terminal 120secured to the body 92 and electrically insulated therefrom. Terminal120 is electrically connected by means of a wire 122 to a suitablesource of power for the 'control circuit. The deceleration detector 90further includes a coil spring 124 having one end thereof in engagementwith the diaphragm 102 and the other end thereof in engagement with thehousing portion 98 so as to bias the diaphragm 102 to maintain thecontacts 110, 115 normally closed when pressure is balanced betweenchambers 104., 106.

In operation the system responds to steady state vehi cle operation andvehicle operation that produces an increasing compressor dischargepressure at the signal conduit 10] to produce a pressure within'thcchambers 104., 106 that is equalized across the orifice 108. Duringthesc'modes of operation the spring 124 will maintain the contacts 110,1 15 closed. This will condition the solenoid 116 to maintain the valve84 to position piston 74 as shown in dotted line in FIG. 2 so as toshift the sleeve 58 into a position to cause the openings 60 therein tooverlie the primary air ports 32 thus to maintain an increased level ofair flow into the combustion chamber 28 which corresponds to anincreased fuel position of throttle 40.

, 4 flow thereto across the valve 36 in accordance with the Underconditions where the vehicle is decelerated by movement of the throttle40 to reduce fuel 'flowto the combustion chamber 28. reduced air flow tothe combustion chamber 28 is required'to maintain a desired air fuelratio to the combustor or burner apparatus 24. Under vehicledeceleration the gas turbine shaft 48 will drive the compressor 12 at areduced speed and will thereby produce a mode of operation wherein thecompressor discharge pressure decreases. Assuming an initial steadystate condition wherein the pressure is balanced across the chambers104, 106 the chamber 106 pressure will be reduced relative to thepressure in chamber 104 in response to the decreased compressordischarge pressure. Moreover, the orifice 108 is sized to besufficiently small so that the pressure in the chamber 104 will bemaintained greater than that in the chamber 106 for a predetermineddelay. This will produce an unbalanced force onthe diaphragm 102 actingto the right as illustrated in FIG. 3, to overcome the spring force tocause it to compress thereby resulting in the contacts 110, 114 beingopened. At thispointthe cnergization of the solenoid 116 will conditionthe valve 84 to position the piston 74 in the solid line position shownin FIG. 2 resulting in arcuate movement of the sleeve 58 to theillustrated position in FIG. 2 to reduce the amount of air flow into thecombustion chamber 28 thereby to maintain a desired air/fuel ratiotherein to control the formation of nitrogen oxides in the burnerassembly 24.

The rate of compressor discharge pressure decrease which is necessary toopen the contacts 110, 115 and the duration of time duringwhich thecontacts will remain open due to the imbalance of pressure across thediaphragm 102 depends upon the volume of the chambers 104, 106 alongwith the preload of the spring 124, its rate and the size of the orifice108. The reduction of air flow into the combustion zone 28 duringdeceleration gives good burner control during vehicle deceleration. Thesystem is eadily adjustable by use of a fine needle valve in place ofthe orifice 108 and an adjustable spring for positioning the fine needlevalve. Such an arrangement permits tailoring of the device for optimumperformance. Another advantage of the arrangement is that thedeceleration detector can also be utilized as a means to detect gasifierdecelerations under engine test conditions'and thus has a use forpurposes other than burner control of the type illustrated in FIGSWhilethe embodiments of the present invention, as herein disclosed.constitute a preferred form. it is to be understood that other formsmight be adopted.

What is claimed is:

1. A deceleration control system for a gas turbine engine comprising:burner apparatus having an outer case for receiving combustion air.compressor means for supplying air to said outer case. a burner linerlocated within said outer case including a combustion zone and adilution zone, throttle means for directing fuel into said combustionzone. a first plurality of primary air ports in said liner for directingair from the outer case into the primary zone. a second plurality ofports in said liner for directing air from the outer case into saiddilution zone. valve means operable to control the ratio of air directedinto the combustion zone and dilution 'zone. turbine means energized bythe burner apparatus connected to drive said compressor means and avehicle power shaft, a decelerator sensor including a pressure sealedhousing having a flexible diaphragm forming first and secondpressurizable chambers within said housing, a signal port in saidhousing for directing dis charge pressure from said compressor meansinto one of said chambers, orifice means located between said first andsecond chambers to maintain a balanced pressure thereacross under steadystate engine operation,

switch: means operated by said diaphragm between open and closedposition, spring means for biasing said diaphragm, to close said switchmeans during steady state compressor discharge pressure operation. meansresponsive to closure of said switch means to condition said valve meansto direct a predetermined amount of compressed air through the primaryair ports in said liner to the combustion zone during steady state andincreasing compressor discharge pressure operation, said firstpressurizable chamber having the pressure therein reduced during enginedeceleration and said orifice means being selected to retain pressure insaid second chamber to produce an unbalanced force across said diaphragmin opposition to said spring means to produce opening of said switchmeans, said valve means being responsive to opening of said switch meansto reduce flow of primary air into said combustion zone to reduce thepower supply to said turbine means under vehicle decelerationconditions.

2. A turbine engine control system for regulating the output temperatureof a burner assembly in accordance with vehicle operation comprising:compressor means having an inlet and an outlet, turbine means includinga power output shaft and means connectedto said compressor means todrive said compressor means in accordance with vehicle acceleration anddeceleration, a burner apparatus including an outer case for receivingcompressed air from said compressor means, a burner liner within saidouter case including primary and secondary air ports therein, acombustion zone within said liner in communication with said primaryports and a dilution zone within said liner in communication with saidsecondary air ports, throttle means for supplying fuel to saidcombustion zone, valve means for varying the proportion of air flow fromthe outer case through said primary and secondary air ports to regulatethe air flow into said combustion zone to control the output temperatureof said burner apparatus, a servo switch including a pressure tighthousing having a movable diaphragm therein separating said housing intofirst and second prcssurizable chambers, a signal port in said housingfor communicating said first chamber with the compressor dischargepressure, orifice means for com municating said first and secondchambers to balance pressure therein in accordance with compressordischarge pressure under steady state and increasing compressordischarge pressure operating conditions, switch means operated by saiddiaphragm between open and closed positions, spring means for biasingsaid diaphragm when pressure is balanced between said first tilincreased quantity of air into said combustion zone, said orifice meansbeing sized to maintain an imbalanced pressure between said first andsecond chamber when the compressor discharge pressure is reduced uponvehicle deceleration to cause said diaphragm to move in opposition tosaid spring means to condition said switch means open, said controlmeans being responsive to opening of said switch means to condition saidvalve means to reduce the amount of air flow into said combustion zonethereby to produce a reduced burner temperature outlet for reducingoutput power from said turbine means under vehicle decelerationconditions of operation.

3. A regenerative gas turbine comprising: in combination, air compressormeans, combustion apparatus supplied from said compressor means saidcombustion apparatus including a combustion products generator includinga combustion zone and a dilution zone, turbine means energized from thecombustion apparatus connected to drive said compressor means, a heatexchanger and a turbine exhaust duct connected through one pass of theheat exchangensaid heat exchanger having a second pass in heat exchangerelation to the first pass, a compressed air conduit leading from thecompressor to said second pass for directing air to the combustionapparatus, said combustion apparatus including a liner having primaryand secondaryair ports therein leading to said combustion zone anddilution zone respectively, valve means for controlling the ratio of airflow from the compressor into said combustion and dilution zones forcontrolling the outlet temperature of said burner apparatus, means fordirecting fuel to said combustion zone including a throttle, saidcombustion apparatus being responsive to a reduced flow of fuel uponvehicle deceleration to produce a reduced temperature in said combustionapparatus with a resultant decrease in output power from said turbinemeans, a deceleration detector including a sealed housing having asignal port thereto for sensing the discharge pres sure of saidcompressor means, a movable diaphragm within said sealed housingseparating it into first and second pressurizable chambers, orificemeans for communicating said first and second chambers to balancepressures therebetween under steady state and increasing compressordischarge pressure operation, switch means operated by said diaphragmbetween open and closed positions, spring means for biasing saiddiaphragm to hold said switch means closed when pressures are equalizedin said first and second chambers during steady state and increasingrnodes of compressor discharge pressure operation, means. responsive toclosure of said contacts to condition said valve means to increase flowof air to said combustion zone, said orifice means being operativeduring a decreasing compressor discharge pressure produced byadeceleration mode of throttle operation to maintain a greater pressurewithin one of said chambers to bias said diaphragm against said springmeans to open said switch means, said control means being responsive toopening of said switch means to condition said valve means to reduce theamount of air flow to the combustion zone.

1. A deceleration control system for a gas turbine engine comprising:burner apparatus having an outer case for receiving combustion air,compressor means for supplying air to said outer case, a burner linerlocated within said outer case including a combustion zone and adilution zone, throttle means for directing fuel into said combustionzone, a first plurality of primary air ports in said liner for directingair from the outer case into the primary zone, a second plurality ofports in said liner for directing air from the outer case into saiddilution zone, valve means operable to control the ratio of air directedinto the combustion zone and dilution zone, turbine means energized bythe burner apparatus connected to drive said compressor means and avehicle power shaft, a decelerator sensor including a pressure sealedhousing having a flexible diaphragm forming first and secondpressurizable chambers within said housing, a signal port in saidhousing for directing discharge pressure from said compressor means intoone of said chambers, orifice means located between said first andsecond chambers to maintain a balanced pressure thereacross under steadystate engine operation, switch means operated by said diaphragm betweenopen and closed position, spring means foR biasing said diaphragm toclose said switch means during steady state compressor dischargepressure operation, means responsive to closure of said switch means tocondition said valve means to direct a predetermined amount ofcompressed air through the primary air ports in said liner to thecombustion zone during steady state and increasing compressor dischargepressure operation, said first pressurizable chamber having the pressuretherein reduced during engine deceleration and said orifice means beingselected to retain pressure in said second chamber to produce anunbalanced force across said diaphragm in opposition to said springmeans to produce opening of said switch means, said valve means beingresponsive to opening of said switch means to reduce flow of primary airinto said combustion zone to reduce the power supply to said turbinemeans under vehicle deceleration conditions.
 2. A turbine engine controlsystem for regulating the output temperature of a burner assembly inaccordance with vehicle operation comprising: compressor means having aninlet and an outlet, turbine means including a power output shaft andmeans connected to said compressor means to drive said compressor meansin accordance with vehicle acceleration and deceleration, a burnerapparatus including an outer case for receiving compressed air from saidcompressor means, a burner liner within said outer case includingprimary and secondary air ports therein, a combustion zone within saidliner in communication with said primary ports and a dilution zonewithin said liner in communication with said secondary air ports,throttle means for supplying fuel to said combustion zone, valve meansfor varying the proportion of air flow from the outer case through saidprimary and secondary air ports to regulate the air flow into saidcombustion zone to control the output temperature of said burnerapparatus, a servo switch including a pressure tight housing having amovable diaphragm therein separating said housing into first and secondpressurizable chambers, a signal port in said housing for communicatingsaid first chamber with the compressor discharge pressure, orifice meansfor communicating said first and second chambers to balance pressuretherein in accordance with compressor discharge pressure under steadystate and increasing compressor discharge pressure operating conditions,switch means operated by said diaphragm between open and closedpositions, spring means for biasing said diaphragm when pressure isbalanced between said first and second chambers to maintain said switchmeans closed, control means responsive to closure of said switch meansto condition said valve means to direct an increased quantity of airinto said combustion zone, said orifice means being sized to maintain animbalanced pressure between said first and second chamber when thecompressor discharge pressure is reduced upon vehicle deceleration tocause said diaphragm to move in opposition to said spring means tocondition said switch means open, said control means being responsive toopening of said switch means to condition said valve means to reduce theamount of air flow into said combustion zone thereby to produce areduced burner temperature outlet for reducing output power from saidturbine means under vehicle deceleration conditions of operation.
 3. Aregenerative gas turbine comprising: in combination, air compressormeans, combustion apparatus supplied from said compressor means saidcombustion apparatus including a combustion products generator includinga combustion zone and a dilution zone, turbine means energized from thecombustion apparatus connected to drive said compressor means, a heatexchanger and a turbine exhaust duct connected through one pass of theheat exchanger, said heat exchanger having a second pass in heatexchange relation to the first pass, a compressed air conduit leadingfrom the compressor to said second pass for directing air to thecombustion apparatus, said combustion apparatus iNcluding a liner havingprimary and secondary air ports therein leading to said combustion zoneand dilution zone respectively, valve means for controlling the ratio ofair flow from the compressor into said combustion and dilution zones forcontrolling the outlet temperature of said burner apparatus, means fordirecting fuel to said combustion zone including a throttle, saidcombustion apparatus being responsive to a reduced flow of fuel uponvehicle deceleration to produce a reduced temperature in said combustionapparatus with a resultant decrease in output power from said turbinemeans, a deceleration detector including a sealed housing having asignal port thereto for sensing the discharge pressure of saidcompressor means, a movable diaphragm within said sealed housingseparating it into first and second pressurizable chambers, orificemeans for communicating said first and second chambers to balancepressures therebetween under steady state and increasing compressordischarge pressure operation, switch means operated by said diaphragmbetween open and closed positions, spring means for biasing saiddiaphragm to hold said switch means closed when pressures are equalizedin said first and second chambers during steady state and increasingmodes of compressor discharge pressure operation, means responsive toclosure of said contacts to condition said valve means to increase flowof air to said combustion zone, said orifice means being operativeduring a decreasing compressor discharge pressure produced by adeceleration mode of throttle operation to maintain a greater pressurewithin one of said chambers to bias said diaphragm against said springmeans to open said switch means, said control means being responsive toopening of said switch means to condition said valve means to reduce theamount of air flow to the combustion zone.